“Natural preservatives and natural antioxidants” are used in Hills Science Plan LIght Dry Cat Food. What does it mean?
I telephoned Hills in the UK and asked what “natural preservatives and natural antioxidants” means. The lady at customer service said that it referred to high levels of vitamin E and C and mentioned “Tocopherols”.
The natural preservatives in the Hill dry cat food I have mentioned (and probably in other dry cat food products made by Hills) are high levels of vitamin C and E. These act as preservatives at higher than usual levels.
The high level of vitamin E in Hills senior, light, dry cat food is incorporated by adding a type of chemical compound called Tocopherols. They have “vitamin E activity”. That must mean they are an artificially produced form of vitamin E but they can be described as “vitamin E” as I understand it.
My research indicates that high doses of vitamin E can increase risk of dying in humans. However other sources state there are no side effects from high doses of vitamin E.
As for vitamin C, high levels can, it seems, cause stones in the urinary tract of cats who are predisposed to urinary oxalate stone formation. Cat owners won’t know if their cat is predisposed. As far as I can tell, other than that, vitamin C is OK at high levels (petmd.com) . However it is not required as a supplement in cat food as the cat can make it themselves (synthesise it) so in this instance it is purely used as a natural preservative.
I can’t find anything in my books that state that overdoses of vitamin E and E cause health problems.
Food preservatives are useful. I sense that the main benefit is for the manufacturer but no doubt consumers also benefit.
Cat food preservatives can be, what I would describe as, nasty chemicals. The ones that constantly come up on the internet are: BHA, BHT, and Ethoxyquin. BHA has the E number E320 and is (butylated hydroxyanisole. BHT is butylated hydroxytoluene. Ethoxyquin is E324 and is also used as a pesticide! That pretty well sums up the chemical.
I’d try and avoid cat food with those preservatives. They can have a potentially damaging impact on cat health. It is tricky to know exactly what is going on. BHT and BHA are also used as preservatives in human food.
Conclusion: As cat food preservatives avoid BHA, BHT, and Ethoxyquin if possible. Vitamin C and E as “natural” preservatives are OK. However, see a vet about this if you are concerned.